Apparatuses and methods have been developed for testing devices having a display without opening the device or connecting any measuring equipment to the device. Such apparatuses may capture frames of the display with an image sensor. Captured frame information is then analysed to determine the quality of video playback. In some methods a certain area of the display is used to display a frame indicator. The frame indicator is for example a square which is shown as a white square by every other frame and as a black square by every other frame. Hence, the area can be imaged at intervals wherein the frame rate can be detected on the basis of the frequency of the varying black and white squares. However, such systems are only capable of testing a receiving device but are not capable of testing a transmission path from a sending device to the receiving device.
Therefore, there is a need to find an improved method, system and apparatus in which video capturing, transmission and/or receiving quality measures may be more reliably performed. The method should also enable the use of very simple test setup.
In this context the term frame is one set of visual information in matrix form to be shown by a display. The frame may be a part of a video content i.e. one frame of a sequence of frames, a picture, etc. The term dropped frame or an omitted frame means a frame of a sequence of frames which is not displayed by the display due to errors in capturing, transmission, reception and/or displaying. The reason for dropping the frame may be, for example, that the capturing device is not fast enough, a transmission path has not enough bandwidth or is not error prone, an input buffer of a receiving device or the display is full, the device controlling the display is occupied by other simultaneous tasks etc. The frame may also be called as an image in this application.